Heat reflecting temporary coating material



Patented July 22, 1941 Orville E. Mohler, Glendale, calla, assignor to'Socony-Vacuum Oil Company, Incorporated,

New York N. I a corporation of New York No Drawing. ApplicationSeptember 1, 1939,

I Serial No. 292,992

1 Claim.

The object of the invention is to provide a heat reflecting, corrosionpreventing coating material for metal surfaces which may readily beremoved when itsusefu lness is at an end.

In such service as, for example, shipping aeroplanes ortheir parts bysea, it is necessary to cover the bright metal parts with a coatingwhich will protect them from corrosion by salt spray, to which thealloys of aluminum are particularly subject.

The compounds heretofore used for that purpose have been dark coloredand cause the absorption by the metal of excessive quantities of heat,causing abnormal expansion and undue stresses in riveted joints,particularly over large surfaces such as wings and bodies.

having a boiling range from 300 to 400 F., and is preferably preparedfrom a naphthenic crude. Such solvent is miscible with any of the aboveresins when molten and gives a clear'solution I propose for thispurpose, a compound con- 'sisting of an oil soluble resin, a solvent,and aluminum powder, brought to the consistency of a moderately thickpaint to be applied witha brush or an air spray. A typical composite forthis purpose may have the following formula:

Petroleum resin per cent 15to 50 Petroleum solvent do 85 to 50 Aluminumpowder pounds per gallon /2 The petroleum resin may be awater-insoluble.

naphthenate of one of the metals, as for example of zinc, copper,calcium, or magnesium, or it may be the residue resulting from thetreatment of petroleum acids with formaldehyde and consist- I ing of theformaldehyde condensation products of phenols, cresols, etc., naturallyoccurring in the crude, or it may be the residue resulting from thedistillation of acid-treated pressure distillate from a petroleumcracking operation, and which consists of condensation products of theunsaturated bodies occurring in such distillate. Some or thenaphthenates of the above metals produce a somewhat sticky coating,while the other resins described, when distilled down to a hard solidconsistency, yield strongly adherent, hard coatlngs, which are stronglyresistant to weathering and to penetration by salt or other-corrosiveagents.

The petroleum solvent should be a distillate which dries rapidly atatmospheric temperature but not toorapidly for application by brushing;

The solutions above are dark in color and those of the second and thirdresins leave a blackish filmon application and when dry. However, whenaluminum powder is added to the solution the leafing action of thealuminum powder causes it to rise to the surface and give a brightaluminum surface irrespective of the dark color of the vehicle.Experiment has shown that aluminum alloy surfaces coated with thefinished product and placed in the noonday sun reached a temperatureaveraging 25 Fahr. below that reached by similarly treated surfaceswhich had been coated with a transparent, dark coloredcorrosion-resisting compound.

All of the above compounds are readily soluble -this they difier fromall the drying oils which on exposure in thin films lose theirsolubility in petroleum distillates and can be removed only withconsiderable difliculty.

I claim as my invention:

A composition for forming a heat-reflecting, corrosion-resisting, easilyremovable coating, comprising: a suspension of aluminum powder in asolution consisting of 15% to naphthenate of a metal selected from thegroup comprising zinc, copper, calcium, and magnesium and to 50% of avolatile petroleum solvent, said suspension'being compounded intheproportions of approximately V2 pound of aluminum powder per gallon ofsaid solution;

ORVIILE E. MOHLER.

